Méthodes : Sur une série de 31 femmes présentant des varices périnéales d’origine extrasaphéniennes ayant bénéficié d’une exploration radiologique veineuse pelvienne et de l’embolisation des veines incontinentes nous avons étudié les résultats et les corrélations anatomo-clinique entre les varices et les signes cliniques de l’insuffisance veineuse pelvienne. Un sous-groupe B de 23 patientes présentant une insuffisance veineuse pelvienne et des signes cliniques a été comparé à un groupe A de 4 patientes qui ne présentaient pas d’insuffisance veineuse pelvienne à l’exploration. Nous avons choisi d’étudier 3 signes cliniques : la douleur pelvienne et la douleur des membres inférieurs survenant au début ou pendant les règles ainsi que la dyspareunie. La symptomatologie a été évaluée sur une échelle analogique de 0 à 10 et un score clinique (de 0 à 30) a été établi en ajoutant ces 3 chiffres.

http://link.springer.com/content/pdf/10.1007/BF02973687.pdf

Références bibliographiques: La fibroscopie bronchique

Oxidation of Metals and Alloys By Dr. O. Kubaschewski and B. E. Hopkins. Pp. xv + 239. (London: Butterworths Scientific Publications, Ltd.; New York: Academic Press, Inc., 1953.) 35s. net.

The Oxidation of Metals

Dense transition metal borides have recently been identified as superhard materials that offer the possibility of ambient pressure synthesis compared to the conventional high pressure, high temperature approach. This feature article begins with a discussion of the relevant physical properties for this class of compounds, followed by a summary of the synthesis and properties of several transition metal borides. A strong emphasis is placed on correlating mechanical properties with electronic and atomic structure of these materials in an effort to better predict new superhard compounds. It concludes with a perspective of future research directions, highlighting some recent results and presenting several new ideas that remain to be tested.

Advancements in the Search for Superhard Ultra-Incompressible Metal Borides

The Brinell, Vickers, Meyer, Rockwell, Shore, IHRD, Knoop, Buchholz, and nanoindentation methods used to measure the indentation hardness of materials at different scales are compared, and main issues and misconceptions in the understanding of these methods are comprehensively reviewed and discussed. Basic equations and parameters employed to calculate hardness are clearly explained, and the different international standards for each method are summarized. The limits for each scale are explored, and the different forms to calculate hardness in each method are compared and established. The influence of elasticity and plasticity of the material in each measurement method is reviewed, and the impact of the surface deformation around the indenter on hardness values is examined. The difficulties for practical conversions of hardness values measured by different methods are explained. Finally, main issues in the hardness interpretation at different scales are carefully discussed, like the influence of grain size in polycrystalline materials, indentation size effects at micro- and nanoscale, and the effect of the substrate when calculating thin films hardness. The paper improves the understanding of what hardness means and what hardness measurements imply at different scales.

/pdf/indentation-hardness-measurements-at-macro-micro-and-3h3klv6hni.pdf

Indentation Hardness Measurements at Macro-, Micro-, and Nanoscale: A Critical Overview

Progress in Materials Science Vol. 9. Edited by Dr. Bruce Chalmers. (Incorporating “Progress in Metal Physics”, Volumes 1–8.) Pp. 389. (London and New York: Pergamon Press, 1961.) 120s. net; 20 dollars.

Progress in Materials Science

The purpose of this investigation was to study the load dependence of the microhardness, typically in the range 5–500 gf. This well known phenomena is called the indentation size effect (ISE) and was investigated for two sets of specimens: titanium and aluminium alloys. Variation of the hardness with applied load was first compared with various existing models and the surface profile, near the indent, was measured by confocal microscopy. The formation of pile-ups near the indentation print led to the correction of the indent diagonal which is found to fit well with our experimental data as well as with other results in the literature. For the materials investigated, the ISE effect is an artefact, i.e. the variation of hardness with the applied load is only a consequence of the variation of the contact surface between the specimen and the indenter.

Indentation size effect: reality or artefact?

Statistical tolerance analysis of bevel gear by tooth contact analysis and Monte Carlo simulation

The paper presents the results of an experimental investigation, done on the friction stir welding (FSW) plunging stage. Previous research works showed that the axial force and torque generated during this stage were characteristic for a static qualification of a FSW machine. Therefore, the investigation objectives are to better understand the relation between the processing parameters and the forces and torque generated. One of the goals is to find a way to reduce the maximum axial force and torque occurring at the end of the plunging stage in order to allow the use of a flexible FSW machine. Thus, the influence of the main plunge processing parameters on the maximum axial force and torque are analysed. In fact, forces and torque responses can be influenced by the processing parameter. At the end, a diagram presenting the maximum axial force and torque according to the processing parameters is presented. It is an interesting way to present the experimental results. This kind of representation can be useful for the processing parameters choice. They can be chosen according to the force and torque responses and consequently to the FSW machine capacities.

/pdf/experimental-investigation-of-the-influence-of-the-fsw-34vnn9ibeo.pdf

Experimental investigation of the influence of the FSW plunge processing parameters on the maximum generated force and torque

The extensive use of appropriate coatings to improve wear resistance, friction coefficient, electrical properties and protection from corrosion has stimulated a growing interest in their mechanical properties, and especially hardness measurements. The objects of this study are to compare the predictions obtained using different models and to understand why it is often reported that the Jonsson and Hogmark model does not hold for indentation prints less than the coating thickness. Methods were reviewed for calculating the composite hardness, and it was found that the simplifications made by the authors are not always valid. By taking in account all the terms of the equations of Jonsson and Hogmark, it was found that the relation between the hardness and the reciprocal length of the indentation print is not linear and depends on the ratio between the film thickness and the indentation print, as well as the variation of the hardness of the substrate and the film with the applied load. Comparison of the Burnett and Rickerby experimental data with the modified model led to very good agreement.

Régis Bigot

Papers

Indentation size effect: reality or artefact?

Statistical tolerance analysis of bevel gear by tooth contact analysis and Monte Carlo simulation

Experimental investigation of the influence of the FSW plunge processing parameters on the maximum generated force and torque

Hardness of coatings

Microstructure and flow behaviour during backward extrusion of semi-solid 7075 aluminium alloy